Nohemi Huanca-Nunez is a Postdoctoral Research Associate at the Yale School of the Environment. Originally from Peru, her research focuses on understanding the origins and maintenance of high levels of tropical species diversity. She is interested in plant ecology, biotic interactions, and the regeneration dynamics of tropical forests.
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Conspecific Density Dependence and the Stature-Recruitment Trade-Off in Tropical Forest Seedlings
N. HUANCA-NUNEZ
, L. BROWNE, L.S. COMITA
Yale School of the Environment, Yale University, New Haven, CT 06520-8354 USA
The dynamics of seedling survival and biodiversity in tropical forests are influenced by conspecific negative density-dependence (CNDD), which varies among species, possibly due to differing life-history strategies. This study investigates whether the variation in CNDD strength among tropical tree species can be explained by two life-history trade-offs: the growth-survival axis and the stature-recruitment axis.
Using data from 815,991 seedlings of 235 species monitored from 2001 to 2018 in a 50-ha plot in Panama, we applied Generalized Additive Models to estimate species-specific mortality and CNDD strength. Meta-regressions linked CNDD variation to life-history axes and functional traits such as wood density, seed mass, and leaf thickness.
Our findings demonstrated that CNDD strength aligns with life-history strategies. Fast-growing species exhibited stronger CNDD compared to their slow-growing counterparts. Additionally, we identified a relationship between CNDD variation and the stature-recruitment trade-off. Specifically, long-lived pioneers showed stronger CNDD than short-lived breeders. Functional traits like wood density and maximum height (but not other leaf traits) were significantly related to variation in CNDD among species.
Our study highlights the importance of considering multiple life-history axes when exploring CNDD variation, suggesting that these trade-offs contribute to species coexistence in tropical forests. Understanding these dynamics is vital for managing and conserving forest biodiversity.